[x/blog] go.blog: fix links in "Introducing Gofix"
[x/blog] go.blog: fix links in "Introducing Gofix"

Fixes golang/go#8692.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/141420043
X-Blog-Commit: 63173935e06d26c8f9295a191577355d6f0d15b7

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website